Russian troops that took over the Chornobyl nuclear power plant last month have transferred control back to Ukraine, the International Atomic Energy Agency said Thursday, citing information from Ukraine.

Multiple convoys of Russian troops in the area have also moved back toward Kremlin-allied Belarus on Ukraine’s northern border, Kyiv told the IAEA.

The Russian forces, which had held the nuclear facility since Feb. 24, “in writing” returned control of the Chornobyl plant to Ukrainian personnel, the IAEA said in a press release.

The agency added that it “has not been able to confirm reports of Russian forces receiving high doses of radiation while being in the Chornobyl Exclusion Zone.”

The IAEA said those Russian troops moved two convoys toward Belarus, while a third convoy left the nearby city of Slavutych, where many of the nuclear plant’s staff live, also toward Belarus.

“In addition, Ukraine reported that there are still some Russian forces on the Chornobyl NPP site but presumed that those forces are preparing to leave,” the IAEA statement said.

U.S. intelligence appeared to back up Ukraine’s information. “We have seen indications that some Russian forces are departing the Chernobyl plant facility,” Pentagon spokesman John Kirby said in a press briefing Thursday afternoon.

“We gather that they are leaving to the north to go back again towards Belarus. But again, indications are not completely clear at this time,” Kirby said.